Tunneling nanostructured materials

Nanostructured materials have also been formed by scanning tunneling microscopy (STM) [24], scanning electrochemical microscopy (SECM) [25], and atomic force microscopy (AFM) [26], Recent reports on the modification of atomic sites at bare surfaces by STM [27] and the formation of nanometer-scale defects by STM [28] and AFM [29] illustrate the power of these techniques. 

Garcia, N. (1991). Scanning tunneling microscopy and force microscopy applied to magnetic materials. In Science and Technology of Nanostructured Materials. Eds. G. C. Hadjipanayis and G. A. Prinz. NATO ASI Series B Physics, Vol. 259. Plenum Press, London, pp. 301-30. 

Nanostructured materials are characterized by ordered structural domains,at the level of nanometers (7). These materials display the properties of condensed matter without a long range order. In general, four types of such materials based on the integral modulation dimensionalities of zero (nanoconfined particles), one (linear tunnel or channel structures two (multilayers) and three (nanophases) are possible (2). The simplest nanostructured materials are the nanoconfined systems of zero modulation dimensionality which consist of a host matrix with a nm-size spatial cavity that can act as an enclosure for dopant molecular particles. The nanostructured materials obtained by encapsulation of biological macromolecules in sol-gel derived porous Si02 structures that contain a trapped bioparticle represent a particularly novel and recent example in this category (5-4). 

There is considerable interest in developing new types of magnetic materials, with a particular hope that ferroelectric solids and polymers can be constructed— materials having spontaneous electric polarization that can be reversed by an electric field. Such materials could lead to new low-cost memory devices for computers. The fine control of dispersed magnetic nanostructures will take the storage and tunability of magnetic media to new levels, and novel tunneling microscopy approaches allow measurement of microscopic hysteresis effects in iron nanowires. 

Phonon-assisted tunneling (PhAT) model has been shown to explain properly nonlinear current-voltage characteristics and temperature dependence of conductivity in carbon nanotubes and other nanostructures of organic materials [1,2], In this paper, we want to show that this model is workable in explanation of I-V characteristics of inorganic nanodevices (Bi xSbx)2Te3 nanowires measured in a wide temperature range, 1.75-350 K, by Xiao et al. [3] and ZnSnOs nanowires presented in [4]. 

The measured dependencies of the conductivity, activation energy and tunnel factor on the concentration of adsorbed oxygen show that the hopping mechanism is realized in nanostructured PTCDI films. The main features of the electrical properties can be explained by means of Fig. 2, where x is the ratio of the adsorbed oxygen concentration to the full concentration of localization centers in the material. Lines A-A and B-B show the theoretical values for intrinsic and impurity... 

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